import { ArgumentMetadata, Injectable, PipeTransform,BadRequestException  } from '@nestjs/common';
import { validate } from 'class-validator';
import { plainToClass } from 'class-transformer';
import { Logger } from '../../utils/log4js';


@Injectable()
export class ValidationPipe implements PipeTransform {
  async transform(value: any, {metatype}: ArgumentMetadata) {
    console.log(`value:`, value, 'metatype: ', metatype);
    if (!metatype || !this.toValidate(metatype)) {
      // 如果没有传入验证规则，则不验证，直接返回数据
      return value;
    }
    // 将对象转换为 Class 来验证
    const object = plainToClass(metatype, value);
    const errors = await validate(object);
    if (errors.length > 0) {
      const msg = Object.values(errors[0].constraints)[0]; // 只需要取第一个错误信息并返回即可
      Logger.error(`Validation failed: ${msg}`);
      throw new BadRequestException(`Validation failed: ${msg}`);
    }
    return value;
  }

  private toValidate(metatype:any):boolean{
    const types: any[]=[String,Boolean,Number,Array,Object];
    return !types.includes(metatype)
  }
}
